Staples in my cupboard/pantry are...
a few types of vinegar
evaporated milk (for cream sauces)
unopened salad dressing (at least a couple)
olive oil, canola oil
cream of mushroom soup (for casseroles and/or soup!)
crushed tomatoes (for sauce)
canned fruit for an emergency
dried fruit
tuna, peanut butter, other kid-friendly items
and a few bay leaves to keep away the pests!
Added on 2-25:
Oh, I forgot some things. Also:
rice
medium grain white rice
a few types of pasta
couscous
canned mushrooms
dried and canned beans/peas
ripe and green olives
tomato soup, vegetable soup
chicken and beef broth
a couple types of gravy
applesauce
mandarin oranges
mayo
a couple types of mustards
ketchup
salsa
pickles
BBQ sauce
bread crumbs
spices include: basil, cumin, oregano, celery seed, dill seed, peppercorns, salt, rosemary,
thyme, sage, cardamom, coriander, tarragon, chili powder, cayenne pepper, paprika, onion powder, garlic powder, ground mustard, fennel, curry powder, cinnamon, cloves, allspice, nutmeg, ginger, and I am sure I am forgetting some
baking powder
baking soda
cream of tartar
corn starch
flavorings (orange, lemon, strawberry, mint, butter, vanilla) for baking
vanilla and choc frosting
walnuts
dates
chocolate chips, butterscotch chips
hot chocolate mix, coffee, tea (herbal and reg)
raisins
canned pumpkin, cherry,
oatmeal, a couple types of cereal
usually just buy meat when I need it, freeze leftovers if we get sick of them
butter
half and half
milk
a selection of deli meats
cheeses - way too many to count
cottage cheese
sour cream
all-purpose flour
white sugar
brown sugar
confectioner sugar
Crisco
molasses
Karo syrup
Freezer items: ice cream, frozen "bargain meats", stock in ice cube trays, and frozen vegetables (spinach, corn, baby peas)